The present invention generally relates to an apparatus for producing scan data by employing a scan key matrix, and more particularly to an apparatus for converting the scan data in which the apparatus provides a variety of operational modes by using an additional mode selecting switch.
Generally, electronic machines to control the various functions thereof have a scan key matrix which enables the machines to arrange the maximum number of keys in the minimum area. Such a scan key matrix circuit usually converts into a binary data of given bits the data selected by one of the multiple keys arranged in a switch block, that is finally activated. The conventional scan key matrix circuit can produce only the scan data of the operational mode depending on the number of the cross points where the rows cross the columns in the matrix, and therefore there is caused the drawback that the number of the keys constituting the scan key matrix limits the number of the output data.
Referring to FIG. 1, the conventional scan data conversion circuit includes a key matrix 12 for producing scan data SD, a scan decoder 14 for decoding the scan data SD, and the first and the second latches 16 and 18 for latching the scan data decoded by the scan decoder 14.
The scan data output from the conventional scan data conversion circuit is transmitted to a key data processing section (not shown) to control the workings and functions of the system. When applied to a scan data conversion system, the conventional scan data conversion circuit is disadvantageous in that an additional scan data conversion circuit must be provided to expand the operational modes of the key matrix switch.